FRCC.PI.006.A2.22 © Danfoss Commercial Compressors 04/10
FRCC.PI.006.A2.22 © Danfoss Commercial Compressors 04/10
Instructions
INSTRUCTIONS
MLZ / MLM COMPRESSORS
10
5
15
20
25
30
35
40
45
50
55
60
65
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
Evap. Temp. (°C)
C
o
n
d
. T
em
p
. (
°C
)
RGT: 18°C
RGT: 25°C
10
15
20
25
30
35
40
45
50
55
60
65
70
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
Evap. Temp. (°C)
C
o
n
d
. T
em
p
. (
°C
)
SH: 11K
15
20
25
30
35
40
45
50
55
60
65
70
75
-20
-15
-10
-5
0
5
10
15
20
Evap. Temp. (°C)
C
o
n
d
. T
em
p
.
(°
C
)
SH: 11K
A
: Model number
B
: Technical number
C
: Serial Number
D
: Internal protection
E
: Supply voltage range
F
: Run capacitor
G
: Locked rotor current
Maximum operating current
H
: Lubricant type and nominal charge
I
: Approved Refrigerant
J
: Manufacturing year
MLZ - R404A / R507
MLZ / MLM - R22
MLZ - R134a
: For transient conditions
Installation and servicing of the
compressor by qualified personnel
only. Follow these instructions and sound
refrigeration engineering practice relating to
installation, commissioning, maintenance and
service.
The compressor must only be used
for its designed purpose(s) and within
its scope of application (refer to «ope-
rating limits»). Consult Application
guidelines and datasheet available
from cc.danfoss.com
Never
operate
compressor
without
terminal box cover
in place and secured.
The compressor is delivered
under nitrogen gas pressure
(between 0.3 and 0.4 bar / 4 and
6 psi). Do not disassemble bolts,
plugs, fittings, etc... unless
all pressure has been relieved
from the compressor.
Under all circumstances,
the EN378 (or other applicable
local safety regulation) requi-
rements must be fulfilled.
Wear protective goggles and
work gloves.
The compressor must
be handled with caution
in the vertical position
(maximum offset from
the vertical : 15°).
N
L₁
Run capacitor
Thermostat
C
S
R
IOL
N
L₁
Thermostat
Start capacitor
Start Relay
5
2
1
15 kΩ -1 w
C
S
R
Run capacitor
M
DGT
HPs
180 s
TH
LP
CONTROL CIRCUIT
F1
F1
KM
KM
KM
KA
KA
A1
A2
A3
KA
KA
KS
KS
KS
L1
L3
L2
Q1
T1
T3
T2
LLSV
KS
Wiring diagram with pump-down cycle
PM
Quick connect spade terminals
P terminal box type
push
push
push
A
B
C
D
E
F
G
H
I
J
PSC wiring
CSR wiring
Operating limits
Electrical connections
Single phase
Three phase (Wiring diagram with pump-down cycle)
Ring connect screw terminals
C terminal box type
C
T₁
S
T₂
R
T₃
• Use clean and dehydrated system components.
• The piping connected to the compressor must be
flexible in 3 dimensions to dampen vibrations.
• The compressor must always be mounted with the
rubber grommets supplied with the compressor.
4 – Assembly
• Slowly release the nitrogen holding charge
through discharge and suction ports.
• Connect the compressor to the system as soon as
possible to avoid oil contamination from ambient
moisture.
• Avoid material entering into the system while cu-
tting tubes. Never drill holes where burrs cannot
be removed.
• Braze with great care using state-of-the-art tech-
nique and vent piping with nitrogen gas flow.
• Connect the required safety and control devices.
When the schrader port, if any, is used for this, re-
move the internal valve.
• For parallel assemblies of the compressors in ver-
sion C8, contact Danfoss.
5 – Leak detection
Never pressurize the circuit with oxygen or dry
air. This could cause fire or explosion.
• Do not use leak detection dye.
• Perform a leak detection test on the complete system.
• The low side test pressure must not exceed 31 bar
/450 psi.
• When a leak is discovered, repair the leak and re-
peat the leak detection.
6 – Vacuum dehydration
• Never use the compressor to evacuate the system.
• Connect a vacuum pump to both the LP & HP sides.
• Pull down the system under a vacuum of
500 µm Hg (0.67 mbar) / 0.02 inch Hg absolute.
• Do not use a megohmmeter nor apply power to
the compressor while it is under vacuum as this
may cause internal damage.
7 – Electrical connections
• Switch off and isolate the main power supply.
• All electrical components must be selected as per
local standards and compressor requirements.
• Refer to page 3 for electrical connections details.
For three phase applications, the terminals are
labeled T1, T2, and T3. For single-phase applica-
tions the terminals are labeled C (common), S
(start), and R (run).
• Danfoss scroll compressors will only compress
gas while rotating counter-clockwise (when
viewed from the compressor top). Since single-
phase motors will start and run in only one di-
rection, reverse rotation is not a major considera-
tion. Three-phase motors, however, will start and
run in either direction, depending on the phase
angles of the supplied power. Care must be taken
during installation to ensure that the compressor
operates in the correct direction.
• Use ø 4.8 mm / #10 - 32 screws and ¼” ring terminals
for the power connection with ring connect screw ter-
minal (C type). Fasten with 3 Nm torque.
• Use ø 6.3 mm tabs for quick connect spade termi-
nals (P type).
• Use a self tapping screw to connect the compres-
sor to earth.
8 – Filling the system
• Keep the compressor switched off.
• Keep the refrigerant charge below the indicated
charge limits if possible. Above this limit; protect the
compressor against liquid flood-back with a pump-
down cycle or suction line accumulator.
• Never leave the filling cylinder connected to the circuit.
Compressor models
Refrigerant
charge limit
MLZ / MLM015-019-021-026
3.6 kg / 8 lb
MLZ / MLM030-038-045-048
5.4 kg / 12 lb
MLZ / MLM058-066-076
7.2 kg / 16 lb
9 – Verification before commissioning
Use safety devices such as safety pressure
switch and mechanical relief valve in compliance
with both generally and locally applicable regu-
lations and safety standards. Ensure that they are
operational and properly set.
Check that the settings of high-pressure swit-
ches don’t exceed the maximum service pressure
of any system component.
• A low-pressure switch is recommended to avoid
low pressure operation.
Minimum setting for R22
1.5 bar (absolute) / 22 psia
Minimum setting for R404A 2.4 bar (absolute) / 35 psia
Minimum setting for R134a 1.45 bar (absolute) / 21 psia
• Verify that all electrical connections are properly
fastened and in compliance with local regula-
tions.
• When a crankcase heater is required, it must be
energized at least 24 hours before initial start-up
and start-up after prolonged shutdown.
10 – Start-up
• Never start the compressor when no refrigerant is
charged.
• Do not provide any power to the compresor
unless suction and discharge service valves are
open, if installed.
• Energize the compressor. It must start promptly.
If the compressor does not start, check wiring
conformity and voltage on terminals.
• Eventual reverse rotation can be detected by fol-
lowing phenomena; the excessive noise, no pres-
sure differential between suction and discharge,
and line warming rather than immediate cooling.
A service technician should be present at initial
start-up to verify that supply power is properly
phased and that the compressor is rotating in the
correct direction. MLZ / MLM Scroll compressors
are designed to operate for a maximum of 150
hours in reverse, but as a reverse rotation situa-
tion can go unnoticed for longer periods, phase
monitors are recommended. For compressors
MLZ / MLM 048 and larger, phase monitors are re-
quired for all applications. Danfoss recommends
phase protection for residential compressors.
• If the internal overload protector trips out, it must
cool down to 60°C / 140°F to reset. Depending on
ambient temperature, this may take up to several
hours.
11 – Check with running compressor
Check current draw and voltage. Measurement
of amps and volts during running conditions must
be taken at other points in the power supply, not in
the compressor electrical box.
• Check suction superheat to reduce risk of slugging.
• Observe the oil level in the sight glass (if provi-
ded) for about 60 minutes to ensure proper oil
return to the compressor.
• Respect the operating limits.
• Check all tubes for abnormal vibration. Move-
ments in excess of 1.5 mm / 0.06 in require cor-
rective measures such as tube brackets.
• When needed, additional refrigerant in liquid phase
may be added in the low-pressure side as far as pos-
sible from the compressor. The compressor must be
operating during this process.
• Do not overcharge the system.
• Never release refrigerant to atmosphere.
• Before leaving the installation site, carry out a
general installation inspection regarding cleanli-
ness, noise and leak detection.
• Record type and amount of refrigerant charge as
well as operating conditions as a reference for fu-
ture inspections.
12 – Maintenance
Internal pressure and surface temperature are
dangerous and may cause permanent injury. Main-
tenance operators and installers require appropria-
te skills and tools. Tubing temperature may exceed
100°C / 212°F and can cause severe burns.
Ensure that periodic service inspections to en-
sure system reliability and as required by local re-
gulations are performed.
To prevent system related compressor problems, fol-
lowing periodic maintenance is recommended:
• Verify that safety devices are operational and pro-
perly set.
• Ensure that the system is leak tight.
• Check the compressor current draw.
• Confirm that the system is operating in a way
consistent with previous maintenance records
and ambient conditions.
• Check that all electrical connections are still ade-
quately fastened.
• Keep the compressor clean and verify the absen-
ce of rust and oxidation on the compressor shell,
tubes and electrical connections.
• Acid / moisture content in system and oil should
be checked regularly.
13 - Warranty
Always transmit the model number and serial num-
ber with any claim filed regarding this product.
The product warranty may be void in following
cases:
• Absence of nameplate.
• External modifications; in particular, drilling, wel-
ding, broken feet and shock marks.
• Compressor opened or returned unsealed.
• Rust, water or leak detection dye inside the com-
pressor.
• Use of a refrigerant or lubricant not approved by
Danfoss.
• Any deviation from recommended instructions per-
taining to installation, application or maintenance.
• Use in mobile applications.
• Use in explosive atmospheric environment.
• No model number or serial number transmitted
with the warranty claim.
14 – Disposal
Danfoss recommends that compressors
and compressor oil should be recycled by
a suitable company at its site.
1 – Introduction
These instructions pertain to the MLZ / MLM scroll com-
pressors used for refrigeration systems. They provide
necessary information regarding safety and proper
usage of this product.
2 – Handling and storage
• Handle the compressor with care. Use the dedica-
ted handles in the packaging. Use the compres-
sor lifting lug and use appropriate and safe lifting
equipment.
• Store and transport the compressor in an upright
position.
• Store the compressor between -35°C and 70°C /
-31°F and 158°F.
• Don’t expose the compressor and the packaging
to rain or corrosive atmosphere.
3 – Safety measures before assembly
Never use the compressor in a flammable atmosphere.
• Mount the compressor on a horizontal flat sur-
face with less than 7° slope.
• Verify that the power supply corresponds to the com-
pressor motor characteristics (see nameplate).
• When installing a compressor for R404A,R507or
R134a, use equipment specifically reserved for HFC
refrigerants which was never used for CFC or HCFC
refrigerants.
• Use clean and dehydrated refrigeration-grade cop-
per tubes and silver alloy brazing material.
3
4
Quick connect spade terminals
P terminal box type
Ring connect screw terminals
C terminal box type
MLZ / MLM
